Specificity and specialization of Dactylogyrus species parasitising cyprinid fish
| Authors | |
|---|---|
| Year of publication | 2005 |
| Type | Article in Proceedings |
| Conference | Sun Yat-Sen University, Guangzhou, China : School of Life Sciences, Sun Yat-Sen University, Guangzhou |
| MU Faculty or unit | |
| Citation | |
| Field | Zoology |
| Keywords | Dactylogyrus - Cyprinidae- molecular phylogeny - host specificity |
| Description | Dactylogyrus species represent a highly diversified parasite group restricted mainly to the fish species of Cyprinidae. A total of 51 Dactylogyrus species parasitizing 19 fish species belonging to the Cyprinidae and one fish species belonging to Percidae were analysed. Several aspects connected with the evolution of host specificity were investigated and tested: (1) host specificity is constrained by parasite phylogeny, (2) specialists evolve from generalists and many specialists arise from specialists, (3) specificity leads to species diversification, (4) the parasite attachment organ is connected with host specificity. Moreover, determinants of host specificity following the hypothesis of specialisation on more predictable resources (maximal host body size, longevity and abundance) were tested. Phylogenetic information obtained from molecular analysis of 18S rDNA and ITS1 of Dactylogyrus and cytochrome b of fish species were included in the analyses. Host specificity was expressed by (1) index of host specificity including phylogenetic and taxonomic relatedness of hosts, and (2) host range. Host specificity was constrained by parasite phylogeny but no significant contribution of host phylogeny was found. Being specialist was shown as an ancestral state for Dactylogyrus species and specificity was not associated with taxonomic diversification. Specialisation on more predictable resource was confirmed, i.e. longer lived fish are colonized by larger-body sized specialists. Specialists with larger anchors tend to live on longer lived and/or larger body sized fish species, which could be interpreted as a mechanism for optimizing the morphological adaptation. No morphometric association between generalist parasites and the traits of their preferred host (selected among all potential hosts colonized by a given generalist parasite) was found. Evolution of morphology of attachment organ is connected with host specificity and fish relatedness. |
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